The Capital Accumulation Model for Economic Growth

Key Insight

Low-income countries can unlock productive potential by shifting workers from low-productivity agriculture to capital-intensive occupations. This necessitates a significant increase in capital stock, encompassing industrial technology, modern management techniques, and essential infrastructure such as electricity, telecoms, ports, airports, roads, railways, and housing. The objective for a poor country, with a capital stock potentially as low as 1.5 times its annual GDP, is to elevate this to levels comparable to advanced economies, which typically possess a capital stock over three times their annual GDP.

Achieving this capital accumulation requires investment to grow substantially faster than GDP over a long period. For example, a country targeting a capital/GDP ratio of 3-to-1 over 30 years, with 6% annual GDP growth, would need its capital stock to grow by 8.5% yearly, nearly doubling its investment rate from 19% to 37%. This pattern was observed in successful East Asian economies like Japan, South Korea, and Taiwan, and in China, whose investment rate rose from 28% to 46% between 1980 and 2010, increasing its capital stock from 1.8 to 2.4 times GDP. Crucially, in the early stages, the marginal efficiency of individual capital projects is secondary to accumulating as much 'appropriate' capital as possible, provided there are basic productivity standards, functioning market institutions, a decent labor force, and a predictable investment environment. This allows new capital to generate high returns due to the 'advantage of backwardness.'

However, this capital-intensive growth model has an inherent expiration date. Once a country's capital stock approaches rich-country levels, the benefits of merely adding more capital diminish. Businesses have sufficient equipment, workers are already highly productive, and most necessary infrastructure is in place. At this juncture, robust economic growth cannot be sustained simply by capital expansion. Instead, growth must pivot to increasing the output per unit of capital, focusing on enhancing resource efficiency. This transition typically leads to a slower rate of economic growth, as the economy relies predominantly on a single source of growth—productivity—rather than the previous two sources of capital addition and productivity improvement. For China, the 'resource mobilization' era is concluding, compelling a shift towards efficiency-driven growth.